Hand-holes are present within the body of welded aluminum light poles. They are used to provide access to the electrical wiring for both installation and maintenance purposes. Wind is the main loading on these slender aluminum light poles and acts in a very cyclic way. In the field, localized fatigue cracking has been observed. This includes areas around hand-holes, most of which are reinforced with a cast insert welded to the pole. This study is focused on an alternative design, specifically hand-holes without reinforcement. Nine poles with 18 openings were fatigue tested in four-point bending at various stress ranges. Among the 18 hand-holes tested, 17 failed in one way or another as a result of fatigue cracking. Typically, fatigue cracking would occur at either the 3:00 or 9:00 positions around the hand-hole and then proceed to propagate transversely into the pole before failure. Finite element analysis was used to complement the experimental study. Models were created with varying aspect ratios to see if the hand-hole geometry had an effect on fatigue life.

中文翻译：

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铝灯杆非增强手孔的疲劳行为

焊接铝灯杆的主体内存在手孔。它们用于为安装和维护目的提供对电线的访问。风是这些细长的铝制灯杆的主要负载，并且以非常循环的方式起作用。在现场，已观察到局部疲劳裂纹。这包括手孔周围的区域，其中大部分区域都用焊接在杆上的铸造插件进行了加固。这项研究的重点是另一种设计，特别是没有加固的手孔。九个具有 18 个开口的杆在不同应力范围内进行了四点弯曲疲劳测试。在测试的 18 个手孔中，有 17 个因疲劳开裂而以某种方式失败。通常，疲劳开裂会在 3:00 或 9 发生：00 位置围绕手孔，然后在失效前继续横向传播到杆中。有限元分析用于补充实验研究。创建具有不同纵横比的模型，以查看手孔几何形状是否对疲劳寿命产生影响。